october 2020 – september 2024
Adam Gregg
My project seeks to further understand bacterial canker resistance through phenotyping and genotyping methods. Previous research has shown that some commercial cherry cultivars exhibit broad-acting partial resistance towards all pathogens. This resistance is likely to be quantitative involving a range of traits, meaning a continuous distribution between resistance and susceptible phenotypes in a progeny resulting from the segregation of alleles with variable effects at several loci. In contrast, wild cherry has been shown to exhibit strong resistance which may result from only a few major genes. Therefore, the understanding of genes which control this strong resistance is key to establishing robust disease-resistant commercial cherry varieties.
Initially, a suite of pathology assays is being developed to understand extent and timings of immune or disease response using different strain-cultivar combinations. These include the measurement of reactive oxygen species, ion leakage, leaf & shoot pathology, cell death and biophoton emission. Future resistance characterization will involve effector/bacterial localization experiments using fluorescent microscopy, and analysis of resistance gene expression through RNA sequencing.
Finally, established multi-parental cherry populations will be genotyped with high depth sequencing of parental founders and shallow (DArT or skim) sequencing of progeny to enable genome wide association studies of resistance to identify candidate loci and genomic prediction for improved breeding strategies.